In a screw-coupled electrical connector, an internally screw-threaded coupling sleeve is mounted on a first of the parts to enable the second connector-part, which is provided with an external screw-thread, to be drawn towards the first part. Hereinafter the expressions "coupling direction of rotation of the coupling sleeve" and "uncoupling direction of rotation of the coupling sleeve" means respectively the directions in which the coupling sleeve is rotated to draw the connector parts together and to enable separation of the two connector parts. It is known to provide screw-coupled electrical connectors with means for providing an indication of the fact that the two parts are approaching or have reached the fully mated condition and for resisting subsequent rotation of the coupling sleeve in the uncoupling direction. To this end it has been proposed to provide a series of circumferentially spaced smaller movable balls mounted in a flange on the first connector part and a series of holes in a flange on the coupling sleeve. As the coupling sleeve is rotated in the coupling direction the balls sequentially engage the holes and in doing so provide audible clicks. When the connector-parts are fully-mated, the engagement between the balls and the holes provides resistance to rotation of the coupling sleeve in the uncoupling direction which could result, for example, from vibration. It has also been proposed to replace the balls and holes by protrusions and indentations which may be defined on washers instead of flanges.